664645550 has 24 divisors (see below), whose sum is σ = 1238576232. Its totient is φ = 265356000.

The previous prime is 664645543. The next prime is 664645567. The reversal of 664645550 is 55546466.

It is a Smith number, since the sum of its digits (41) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 664645498 and 664645507.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14765 + ... + 39335.

It is an arithmetic number, because the mean of its divisors is an integer number (51607343).

Almost surely, 2^664645550 is an apocalyptic number.

664645550 is a deficient number, since it is larger than the sum of its proper divisors (573930682).

664645550 is a wasteful number, since it uses less digits than its factorization.

664645550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25124 (or 25119 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 41.

The square root of 664645550 is about 25780.7205097142. The cubic root of 664645550 is about 872.6967670872.

The spelling of 664645550 in words is "six hundred sixty-four million, six hundred forty-five thousand, five hundred fifty".